This invention relates to a series of amino pyrazole derivatives, pharmaceutical compositions containing them and intermediates used in their preparation. The compounds of the invention are ligands for the neuropeptide Y subtype 5 (NPY5) receptor, a receptor which is associated with a number of central nervous system disorders and affective conditions.
Regulation and function of the mammalian central nervous system is governed by a series of interdependent receptors, neurons, neurotransmifters, and proteins. The neurons play a vital role in this system, for when externally or internally stimulated, they react by releasing neurotransmitters that bind to specific proteins. Common examples of endogenous small molecule neurotransmitters such as acetylcholine, adrenaline, norepinephrine, dopamine, serotonin, glutamate, and gamma-aminobutyric acid are well known, as are the specific receptors that recognize these compounds as ligands (xe2x80x9cThe Biochemical Basis of Neuropharmacologyxe2x80x9d, Sixth Edition, Cooper, J. R.; Bloom, F. E.; Roth, R. H. Eds., Oxford University Press, New York, N.Y. 1991).
In addition to the endogenous small molecule neurotransmitters, there is increasing evidence that neuropeptides play an integral role in neuronal operations. Neuropeptides are now believed to be co-localized with perhaps more than one-half of the 100 billion neurons of the human central nervous system. In addition to humans, neuropeptides have been discovered in a number of animal species. In some instances the composition of these peptides is remarkably homogenous among species. This finding suggests that the function of neuropeptides is vital and has been impervious to evolutionary changes. Furthermore, neuropeptides, unlike small molecule neurotransmitters, are typically synthesized by the neuronal ribosome. In some cases, the active neuropeptides are produced as part of a larger protein that is enzymatically processed to yield the active substance. Based upon these differences, compared to small molecule neurotransmitters, neuropeptide-based strategies may offer novel therapies for CNS diseases and disorders. Specifically, agents that affect the binding of neuropeptides to their respective receptors or ameliorate responses that are mediated by neuropeptides are potential therapies for diseases associated with neuropeptides.
There are a number of afflictions that are associated with the complex interdependent system of receptors and ligands within the central nervous system; these include neurodegenerative diseases, affective disorders such as anxiety, depression, pain and schizophrenia, and affective conditions that include a metabolic component, namely obesity. Such conditions, disorders and diseases have been treated with small molecules and peptides which modulate neuronal responses to endogenous neurotransmitters.
One example of the class of neuropeptides is neuropeptide Y (NPY). NPY was first isolated from porcine brain (Tatemoto, K. et al. Nature 1982, 296, 659) and was shown to be structurally similar to other members of the pancreatic polypeptide (PP) family such as peptide YY, which is primarily synthesized by endocrine cells in the gut, and pancreatic polypeptide, which is synthesized by the pancreas. Neuropeptide Y is a single peptide protein that consists of thirty-six amino acids containing an amidated C-terminus. Like other members of the pancreatic polypeptide family, NPY has a distinctive conformation that consists of an N-terminal polyproline helical region and an amphiphilic a-helix joined by a characteristic PP-fold (Vladimir, S. et. Al. Biochemistry 1990, 20, 4509). Furthermore, NPY sequences from a number of animal species have been elucidated and all show a high degree of amino acid homology to the human protein ( greater than 94% in rat, dog, rabbit, pig, cow, sheep) (see Larhammar, D. in xe2x80x9cThe Biology of Neuropeptide Y and Related Peptidesxe2x80x9d, Colmers, W. F. and Wahlestedt, C. Eds., Humana Press, Totowa, N.J. 1993).
Endogenous receptor proteins that bind NPY and related peptides as ligands have been identified and distinguished, and several such proteins have been cloned and expressed. Six different receptor subtypes [Y1, Y2, Y3, Y4(PP), Y5, Y6 (formerly designated as a Y5 receptor)] are recognized today based upon binding profile, pharmacology and/or composition if identity is known (Wahlestedt, C. et. al. Ann. NYAcad. Sci. 1990, 611, 7; Larhammar, D. et. al. J. Biol. Chem. 1992, 267, 10935; Wahlestedt, C. et. al. Regul. Pept, 1986, 13, 307; Fuhlendorff, J. U. et. al. Proc. Natl. Acad. Sci. USA 1990, 87, 182; Grundemar, L. et. al. J. Pharmacol. Exp. Ther. 1991, 258, 633; Laburthe, M. et. al. Endocrinology 1986, 118, 1910; Castan, I. et. al. Endocrinology 1992, 131, 1970; Gerald, C. et. al. Nature 1996, 382, 168; Weinberg, D. H. et. al. Journal of Biological Chemistry 1996, 271, 16435; Gehlert, D. et. al. Current Pharmaceutical Design 1995, 1, 295; Lundberg, J. M. et. al. Trends in Pharmaceutical Sciences 1996, 17, 301). Most and perhaps all NPY receptor proteins belong to the family of so-called G-protein coupled receptors (GPCRs). The neuropeptide Y5 receptor, a putative GPCR, is negatively coupled to cellular cyclic adenosine monophosphate (cAMP) levels via the action of adenylate cyclase (Gerald, C. et. al. Nature 1996, 382, 168; Gerald, C. et. al. PCT WO 96/16542). For example, NPY inhibits forskolin-stimulated cAMP production/levels in a neuroblastoma cell line. A Y5 ligand that mimics NPY in this fashion is an agonist whereas one that competitively reverses the NPY inhibition of forskolin-stimulated cAMP production is an antagonist.
Neuropeptide Y itself is the archetypal substrate for the NPY receptors and its binding can elicit a variety of pharmacological and biological effects in vitro and in vivo. When administered to the brain of live animals (intracerebroventricularly (icv) or into the amygdala), NPY produces anxiolytic effects in established animal models of anxiety such as the elevated plus-maze, Vogel punished drinking and Geller-Seifter""s bar-pressing conflict paradigms (Heilig, M. et. al. Psychopharmacology 1989, 98, 524; Heilig, M. et. al. Reg. Peptides 1992, 41, 61; Heilig, M. et. al. Neuropsycho-pharmacology 1993, 8, 357). Thus compounds that mimic NPY are postulated to be useful for the treatment of anxiolytic disorders.
The immunoreactivity of neuropeptide Y is notably decreased in the cerebrospinal fluid of patients with major depression and those of suicide victims (Widdowson, P. S. et. al. Journal of Neurochemistry 1992, 59, 73), and rats treated with tricyclic antidepressants display significant increases of NPY relative to a control group (Heilig, M. et. al. European Journal of Pharmacology 1988, 147, 465). These findings suggest that an inadequate NPY response may play a role in some depressive illnesses, and that compounds that regulate the NPY-ergic system may be useful for the treatment of depression.
Neuropeptide Y improves memory and performance scores in animal models of learning (Flood, J. F. et. al. Brain Research 1987, 421, 280) and therefore may serve as a cognition enhancer for the treatment of neurodegenerative diseases such as Alzheimer""s Disease (AD) as well as AIDS-related and senile dementia.
Elevated plasma levels of NPY are present in animals and humans experiencing episodes of high sympathetic nerve activity such as surgery, newborn delivery and hemorrhage (Morris, M. J. et. al. Journal of Autonomic Nervous System 1986, 17, 143). Thus chemical substances that alter the NPY-ergic system may be useful for alleviating the condition of stress.
Neuropeptide Y also mediates endocrine functions such as the release of luteinizing hormone (LH) in rodents (Kalra, S. P. et. al. Frontiers in Neuroendrocrinology 1992, 13, 1). Since LH is vital for mammalian ovulation, a compound that mimics the action of NPY could be useful for the treatment of infertility, particularly in women with so-called luteal phase defects.
Neuropeptide Y is a powerful stimulant of food intake; as little as one-billionth of a gram, when injected directly into the CNS, causes satiated rats to overeat (Clark, J. T. et. al. Endocrinology 1984, 115, 427; Levine, A. S. et. al. Peptides 1984, 5, 1025; Stanley, B. G. et. al. Life Sci. 1984, 35, 2635; Stanley, B. G. et. al. Proc. Nat. Acad. Sci. USA 1985, 82, 3940). Thus NPY is orexigenic in rodents but not anxiogenic when given intracerebroventricularly and so antagonism of neuropeptide receptors may be useful for the treatment of eating disorders such as obesity, anorexia nervosa and bulimia nervosa.
In recent years, a variety of potent, structurally distinct small molecule Y1 antagonists has been discovered and developed (Hipskind, P. A. et. al. Annu. Rep. Med. Chem. 1996, 31, 1-10; Rudolf, K. et. al. Eur. J. Pharmacol. 1994, 271, R11; Serradeil-Le Gal, C. et. al. FEBS Lett. 1995, 362, 192; Wright, J. et. al. Bioorg. Med. Chem. Lett. 1996, 6, 1809; Poindexter, G. S. et. al. U.S. Pat. No. 5,668,151; Peterson, J. M. et. al. WO9614307 (1996)). However, despite claims of activity in rodent models of feeding, it is unclear if inhibition of a feeding response can be attributed to antagonism of the Y1 receptor.
Several landmark studies strongly suggest that an xe2x80x9catypical Y1xe2x80x9d receptor and/or the Y5 receptor, rather than the classic Y1 receptor, is responsible for invoking NPY-stimulated food consumption in animals. It has been shown that the NPY fragment NPY2-36 is a potent inducer of feeding despite poor binding at the classic Y1 receptor (Stanley, B. G. et. al. Peptides 1992, 13, 581). Conversely, a potent and selective Y1 agonist has been reported to be inactive at stimulating feeding in animals (Kirby, D. A. et. al. J. Med. Chem. 1995, 38, 4579). More pertinent to the invention described herein, [D-Trp32]NPY, a selective Y5 receptor activator has been reported to stimulate food intake when injected into the hypothalamus of rats (Gerald, C. et. al. Nature 1996, 382, 168). Since [D-Trp32 ]NPY appears to be a full agonist of the Y5 receptor with no appreciable Y1 activity, the Y5 receptor is hypothesized to be responsible for the feeding response. Accordingly compounds that antagonize the Y5 receptor should be effective in inhibiting food intake, particularly that stimulated by NPY.
Sulfanilamidopyrazoles used in hypoglycemic compositions are disclosed in Belgian Patent 655,242 and GB Patent No. 1,054,278. 3,4-substituted pyrazoles as inhibitors of phosphodiesterase are disclosed by Cavalla et al., in PCT WO 96/00218. Nitrogen containing heteroaromatics as factor Xa inhibitors are disclosed by Pinto et al., in PCT WO 98/28269, while Shapiro, H. K., in PCT WO 92/14456 discloses the use of pyrazole derivatives in pharmaceuticals for the treatment of neurological disorders. Certain 1-tolylsulfonyl-pyrazole derivatives are described by Nam, et al. (Izv. Timityazevsk. S-kh. Akad. 1998, 3,201).
1-phenyl substituted aminopyrazole derivatives and their Tensmeyer substituent increments for NMR spectral profiles are described by Ege, G. and Franz, H, J. (Heterocyclic Chem., 1984, 21, 689) and Cativeiela, et al. (Anales De Quimica, 1987, 83, 278). The synthesis of 5-substituted aminopyrazole derivatives is described by Watson, S. P., et al. (Tetrahedron Letters, 1997, 38 (52), 9065). Takigawa et al., in EP 0350176 disclose a method for the synthesis of pyrazolecarboxylic acid and derivatives, while El-Sherief et al. (J. Chem. Res., Synop. 1997, 9, 322) describe the synthesis of 2-(5-amino-3-arylpyrazol-1-yl)-3-methylquinoxalines.
Substituted amino pyrazole derivatives useful as herbicides are disclosed by Kirsten, et al., in U.S. Pat. No. 4,941,912. Pesticidal 1-polyarylpyrazoles are disclosed by Herman, et al. in EP 0839810. Janiak, M. in U.S. Pat. No. 3,592,890 discloses the use of 5-(para-aminobenzenesulfonylamido)-1-phenyl-3-methyl-pyrazole for combating atrophic rhinitis as a prophylactic veterinary method. Weyer et al., in U.S. Pat. No 3,198,791 disclose sulfanilamidopyrazole derivatives and a process for their preparation. Roth, S. H., in U.S. Pat. No. 3,769,076 discloses intumescent compositions containing arylsulfonylaminopyrazoles and imidazoles. Substituted aminopyrazoles as components in silver halide colour photographic light sensitive material are disclosed by Kida et al., in EP 0530011.
The present invention provides novel amino pyrazole derivative compounds useful as ligands of the neuropeptide Y, subtype 5 receptor. More particularly, the present invention is directed to compounds of the general of the formula (I): 
wherein
R1 and R2 are each independently selected from the group consisting of hydrogen, C1-C6alkyl, sulfonylamino, and unsubstituted or substituted arylsulfonyl; wherein the substituents on the arylsulfonyl are one or more substituents independently selected from halogen, C1-C6alkyl, C1-C6alkoxy, trifluoromethyl or trifluoromethoxy;
R3 is selected from the group consisting of unsubstituted or substituted aryl and unsubstituted or substituted heteroaryl; wherein the substituents on the aryl or heteroaryl are one or more substituents independently selected from halogen, C1-C6alkyl, C1-C6alkoxy, trifluoromethyl, trifluoromethoxy, amino, C1-C6alkylamino or di(C1-C6alkyl)amino;
L is selected from the group consisting of unsubstituted or substituted aryl, unsubstituted or substituted heteroaryl and C3-C8cycloalkyl; wherein the substituents on the aryl or heteroaryl are one or more substituents independently selected from halogen, C1-C4alkyl or trifluoromethyl;
n is an integer selected from 0 or 1;
X is selected from the group consisting of sulfonylamino, aminocarbonyl, carbonyl, carbonylamino, sulfonyl, 
sulfonylaminoC1-C6alkyl, C1-C6alkylaminosulfonyl, and di(unsubstituted or substituted arylsulfonyl)amino; wherein the substituents on the aryl group are one or more substituents independently selected from halogen, C1-C6alkyl, C1-C6alkoxy, trifluoromethyl, trifluoromethoxy, C1-C6alkylcarbonylamino, amino, C1-C6alkylamino or di(C1-C6alkyl)amino, and wherein the two aryl groups of the di(unsubstituted or substituted arylsulfonyl)amino have the same substitution pattern;
R4 is selected from the group consisting of hydrogen, C1-C6alkyl, unsubstituted or substituted aryl, C1-C6aralkyl, unsubstituted or substituted heteroaryl and unsubstituted or substituted heterocycloalkyl; wherein the substituents on the aryl, heteroaryl or heterocycloalkyl are one or more substituents independently selected from halogen, C1-C6alkyl, C1-C6alkoxy, trifluoromethyl, trifluoromethoxy, amino, C1-C6alkylamino, di(C1-C6alkyl)amino, nitro or cyano;
p is an integer selected from 0 or 1;
R5 is selected from the group consisting of hydrogen, halogen, C1-C4alkyl and trifluoromethyl;
provided that when X is di(unsubstituted or substituted arylsulfonyl)amino then p is 0; and
provided that when R1 and R5 are both hydrogen, and R3 is phenyl, or methylphenyl, and n is 1, and L is phenyl, and X is sulfonylamino, and R2 is methylphenylsulfonyl, then R4 is selected from the group consisting of hydrogen, C1-C6alkyl, unsubstituted or substituted aryl, wherein the substituents on the aryl are one or more substituents independently selected from halogen, C2-C6alkyl, C1-C6alkoxy, trifluoromethyl, trifluoromethoxy, amino, C1-C6alkylamino, di(C1-C6alkyl)amino, nitro or cyano; C1-C6aralkyl, unsubstituted or substituted heteroaryl and unsubstituted or substituted heterocycloalkyl; wherein the substituents on the heteroaryl or heterocycloalkyl are one or more independently selected from halogen, C1-C6alkyl, C1-C6alkoxy, trifluoromethyl, trifluoromethoxy, amino, C1-C6alkylamino, di(C1-C6alkyl)amino, nitro or cyano; [in other words, when R1 and R5 are both hydrogen, and R3 is phenyl or methylphenyl, and n is 1, and L is phenyl, and X is sulfonylamino, and R2 is methylphenylsulfonyl, then R4 is not methylphenyl];
and pharmaceutically acceptable salts thereof.
Illustrative of the invention is a pharmaceutical composition comprising a pharmaceutically acceptable carrier and any of the compounds described above. An illustration of the invention is a pharmaceutical composition made by mixing any of the compounds described above and a pharmaceutically acceptable carrier. Illustrating the invention is a process for making a pharmaceutical composition comprising mixing any of the compounds described above and a pharmaceutically acceptable carrier.
Exemplifying the invention is a method of treating a condition mediated by the NPY Y5 receptor in a subject in need thereof comprising administering to the subject a therapeutically effective amount of any of the compounds or pharmaceutical compositions described above.
An example of the invention is a method for treating a condition selected from eating disorder, obesity, bulimia nervosa, diabetes, binge eating, anorexia nervosa, dyslipidimia, hypertension, memory loss, epileptic seizures, migraine, sleep disturbances, pain, sexual/reproductive disorders, depression, anxiety, cerebral hemorrhage, shock, congestive heart failure, nasal congestion or diarrhea in a subject in need thereof comprising administering to the subject an effective amount of any of the compounds or pharmaceutical compositions described above.
Further illustrating the invention is the use of a compound of formula (I) in the preparation of a medicament for treating conditions mediated by the NPY Y5 receptor.
The present invention provides novel amino pyrazole derivative compounds useful as ligands of the neuropeptide Y, subtype 5 receptor. More particularly, the present invention is directed to compounds of the general of the formula (I): 
wherein R1, R2 R3, R4, R5, L, X, n and p are as previously defined, and pharmaceutically acceptable salts thereof.
For use in medicine, the salts of the compounds of this invention refer to non-toxic xe2x80x9cpharmaceutically acceptable salts.xe2x80x9d Other salts may, however, be useful in the preparation of compounds according to this invention or of their pharmaceutically acceptable salts. Suitable pharmaceutically acceptable salts of the compounds include acid addition salts which may, for example, be formed by mixing a solution of the compound with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, sulfuric acid, fumaric acid, maleic acid, succinic acid, acetic acid, benzoic acid, citric acid, tartaric acid, carbonic acid or phosphoric acid. Furthermore, where the compounds of the invention carry an acidic moiety, suitable pharmaceutically acceptable salts thereof may include alkali metal salts, e.g., sodium or potassium salts; alkaline earth metal salts, e.g., calcium or magnesium salts; and salts formed with suitable organic ligands, e.g., quaternary ammonium salts. Thus, representative pharmaceutically acceptable salts include the following:
acetate, benzenesulfonate, benzoate, bicarbonate,
bisulfate, bitartrate, borate, bromide, calcium edetate, camsylate, carbonate, chloride, clavulanate, citrate, dihydrochloride, edetate, edisylate, estolate, esylate, fumarate, gluceptate, gluconate, glutamate, glycollylarsanilate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate, lactobionate, laurate, malate, maleate, mandelate, mesylate, methylbromide, methylnitrate, methylsulfate, mucate, napsylate, nitrate, N-methylglucamine ammonium salt, oleate, pamoate (embonate), palmitate, pantothenate, phosphate/diphosphate, polygalacturonate, salicylate, stearate, sulfate, subacetate, succinate, tannate, tartrate, teoclate, tosylate, triethiodide and valerate.
The present invention includes within its scope prodrugs of the compounds of this invention. In general, such prodrugs will be functional derivatives of the compounds which are readily convertible in vivo into the required compound. Thus, in the methods of treatment of the present invention, the term xe2x80x9cadministeringxe2x80x9d shall encompass the treatment of the various disorders described with the compound specifically disclosed or with a compound which may not be specifically disclosed, but which converts to the specified compound in vivo after administration to the patient. Conventional procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in xe2x80x9cDesign of Prodrugsxe2x80x9d, ed. H. Bundgaard, Elsevier, 1985.
Where the compounds according to this invention have at least one chiral center, they may accordingly exist as enantiomers. Where the compounds possess two or more chiral centers, they may additionally exist as diastereomers. It is to be understood that all such isomers and mixtures thereof are encompassed within the scope of the present invention. Furthermore, some of the crystalline forms for the compounds may exist as polymorphs and as such are intended to be included in the present invention. In addition, some of the compounds may form solvates with water (i.e., hydrates) or common organic solvents, and such solvates are also intended to be encompassed within the scope of this invention.
The amino pyrazoles of formula (I) that comprise this invention may be synthesized via the routes outlined in Schemes 1-7, described in more detail below.
Compounds of formula (I) wherein X is -sulfonylamino- and L is -phenyl-, may be prepared according to the process outlined in Scheme 1. 
More specifically, a suitably substituted xcex1-bromoketone of formula (II), a known compound or compound prepared by known methods, is reacted with cyanide, in the presence of an alcoholic solvent such as ethanol, methanol, and the like, with heating from ambient temperature to reflux, to afford the corresponding xcex1-cyanoketone of formula (III).
The xcex1-cyanoketone of formula (III) is coupled with a suitably substituted hydrazine of formula (IV), in the presence of a base such as triethylamine (TEA), diisopropylethylamine (DIPEA), and the like, in an alcoholic solvent such as ethanol, methanol, and the like, with heating from ambient temperature to reflux, to provide the corresponding pyrazole of formula (V).
The pyrazole of formula (V) is treated with hydrogen gas, which gas is applied at a pressure in the range of ambient to 100 p.s.i., in an inert hydrocarbon, ethereal or alcohol solvent, such as methanol, ethanol, and the like, in the presence of a catalyst such as palladium on carbon, platinum oxide, Raney nickel, and the like, with heating from ambient temperature to reflux, to yield the corresponding compound of formula (VI).
The compound of formula (VI) is coupled with a suitably substituted sulfonyl chloride of formula (VII), in the presence of a base such as potassium carbonate, cesium carbonate, and the like, in the presence of water and an ethereal solvent such as THF, diethyl ether and the like, to provide the corresponding aminopyrazole of formula (Ia).
To prepared compounds of formula (I) wherein X is 
the compound of formula (Ia) may be further reacted with a halogenated (C1-C6alkyl)(C1-C6alkyl)ether and a phase transfer catalyst such as benzyl triethyl ammonium chloride, in the presence of water, in the presence of a base such as potassium carbonate, cesium carbonate, and the like, in a halogenated organic solvent such as methylene chloride, chloroform and the like.
Alternatively, the compound of formula (VI) may be reacted to prepare a compound of formula (I) wherein X is di(substituted sulfonyl)imino- and L is -phenyl-, according to Scheme 2. 
Accordingly, the compound of formula (VI) is reacted with a suitably substituted sulfonyl chloride of formula (VII), in the presence of at least one equivalent, preferably about three equivalents, of a base such as triethylamine, diisopropylethylamine, and the like, and a halogenated solvent such as methylene chloride, carbon tetrachloride, and the like, with heating from ambient temperature to reflux, to afforded the corresponding aminopyrazole of formula (Ib).
Alternatively, the compound of formula (VI) may be reacted to prepare a compound of formula (I) wherein X is -carbonylamino- and L is -phenyl-, according to the process outline in Scheme 3. 
Accordingly, the compound of formula (VI) is reacted with an acylating reagent such as an acid chloride of formula (VIII), in the presence of halogenated organic solvent such as methylene chloride, carbon tetrachloride, and the like, to yield the corresponding aminopyrazole of formula (Ic).
Compounds of formula (I) wherein X is -sulfonylamino-, L is -phenyl- and R4 is a mono- or di-substituted aminophenyl, may be prepared according to the process outlined in Scheme 4. 
More specifically, the compound of formula (VI) is reacted with a nitro substituted aryl sulfonyl chloride of formula (IX), wherein Ar represents an aryl group, in the presence of base such as potassium carbonate, cesium carbonate, and the like, and an aqueous ethereal solvent such as aqueous THF, and the like, with heating from at ambient temperature to reflux, to yield the corresponding compound of formula (X).
The compound of formula (X) is reacted with hydrogen gas, at a pressure in the range of ambient to 100 p.s.i., preferably at a pressure between 40-50 p.s.i., in the presence of a suitable catalyst such as palladium on carbon, platinum oxide, and the like, in an inert hydrocarbon, ethereal ester or alcohol solvent, such as hexane, ethyl acetate, methanol, ethanol, and the like, with heating from ambient temperature to reflux, to yield the corresponding compound of formula (XI).
The compound of formula (XI) is reacted with formaldehyde, in acetonitrile, in the presence of an acid such as acetic acid, and the like, and in the presence of a reducing agent such as sodium cyanoborohydride, sodium tetracetoxyborohydride, and the like, to afford a mixture of the corresponding methylated aminopyrazoles, compounds of formula (Id), (Ie) and (If), respectively. Preferably, the compounds of formula (1d), (le) and (If) are separated by known methods, such as flash chromatography.
Compounds of formula (I) wherein X is -aminocarbonyl- and n is 0 (such that L is absent), may be prepared according to the process as outlined in Scheme 5. 
Accordingly, a suitably substituted compound of fotrmula (XII), a known compound or compound prepared by known methods, is reacted with diethyl oxalate, in the presence of a base such as sodium ethoxide, sodium methoxide, and the like, in an ethereal solvent such as diethyl ether, tetrahydrofuran, and the like, at a temperature between 0xc2x0 C. and ambient temperature, preferably at about 0xc2x0 C., to yield the corresponding compound of formula (XIII).
The compound of formula (XIII) is reacted with a suitably substituted hydrazine of formula (IV), in an aqueous halogenated solvent such as aqueous carbon tetrachloride, methylene chloride, and the like, in the presence of an acid such as sulfuric acid, hydrochloric acid, and the like, to afford the corresponding amino pyrazole ester of formula (XIV).
The amino pyrazole ester of formula (XIV) is hydrolyzed using a base such as aqueous sodium hydroxide, lithium hydroxide, and the like, in an aqueous alcohol such as aqueous ethanol, methanol, and the like, with heating from ambient temperature to reflux, to afford the corresponding carboxylic acid of formula (XV).
The carboxylic acid of formula (XV) is coupled to a suitably substituted amine of formula (XV), in the presence of a coupling reagent such as HATU, and the like, in the presence of a sterically hindered amine such as diisopropylethylamine (DIPEA), triethylamine (TEA), and the like, in a solvent such as DMF, and the like, at ambient temperature, to produce the corresponding aminopyrazole of formula (Ig).
Compounds of formula (I) wherein X is -aminocarbonyl-, L is -phenyl- and R1 is hydrogen or phenylsulfonyl and R2 is phenylsulfonyl, may be prepared according to the process outlined in Scheme 6. 
More specifically, methyl-4-(cyanoacetyl) benzoate is reacted with a suitably substituted hydrazine of formula (IV), in an alcoholic solvent such as ethanol, methanol, and the like, with heating from ambient temperature to reflux, to yield the corresponding compound of formula (XVII).
The compound of formula (XVII) is reacted with phenylsulfonyl chloride of formula (XVIII), in a halogentaed organic solvent such as methylene chloride, carbon tetrachloride, and the like, in the presence of pyridine, to yield the corresponding compound of formula (XIX).
The compound of formula (XIX) is hydrolyzed in the presence of an aqueous base such as sodium hydroxide, lithium hydroxide, and the like, to produce the corresponding carboxylic acid of formula (XX).
The compound of formula (XX) is coupled with a suitably substituted amine of formula (XVI), in the presence of a coupling agent such as HATU, and the like, in a base such as diisopropylethylamine (DIPEA), triethylamine (TEA), and the like, in the presence of a reagent such as HOBT and DMAP, and the like, to afford the corresponding aminopyrazole of formula (Ih).
In compounds of formula (I) wherein R4 is a cyclic secondary amine, the compound of formula (XX) is coupled directly with the cyclic secondary amine, in the presence of a coupling agent such as HATU, and the like, in a base such as diisopropylethylamine (DIPEA), triethylamine (TEA), and the like, in the presence of a regent such as HOBT and DMAP, and the like, to produce the corresponding compound of formula (I).
For compounds of formula (I) wherein R1 and R2 are both phenylsulfonyl, the compound of formula (XVII) is reacted with at least two equivalents of the phenylsulfonyl chloride of formula (XVIII) to yield the corresponding bis(phenylsulfonyl)amino substituted compound of formula (XIX) Compounds of formula (I) wherein L is -phenyl- or -cyclohexyl- and X is -sulfonylaminoalkyl-, wherein the amino group may be optionally substituted, may be produced according to the process outlined in Scheme 7. 
Accordingly, a compound of formula (XXI), wherein the symbol 
represents -phenyl- or -cyclohexyl-, a known compound or compound prepared by known methods, is reacted with t-butyl chloroformate to yield the corresponding mixed anhydride of formula (XXII).
An xcex1-nitrile of formula (XXII), a known compound, is reacted with a base such as NaH, KH, NaOCH3, and the like, to produce the corresponding anion of formula (XXIV).
The mixed anhydride of formula (XXII) is reacted with the anion of formula (XXIV), at ambient temperature, to yield the corresponding xcex1-nitrile-xcex2-ketone of formula (XXV).
The compound of formula (XXV) is deprotected by removing the t-butoxycarbonyl (BOC) protecting group with an acid such as trifluoroacetic acid (TFA), hydrochloric acid, and the like, to produce the corresponding compound of formula (XXVI).
The compound of formula (XXVI) is coupled with a suitably substituted hydrazine of formula (IV), in the presence of a base such as triethylamine (TEA), diisopropylethylamine (DIPEA), and the like, with heating from ambient temperature to reflux, to yield the corresponding aminopyrazole of formula (Ij).
Preferably, when L is -cyclohexyl- the compound of formula (XXI) is present in the trans configuration, resulting in the trans isomer of the compound of formula (Ij).
It is generally preferred that the respective product of each process step be separated from other components of the reaction mixture and then subjected to purification before its use as a starting material in a subsequent step. Separation techniques typically include evaporation, extraction, precipitation and filtration. Purification techniques typically include column chromatography (Still, W. C. et. al., J. Org. Chem. 1978, 43, 2921), thin-layer chromatography, crystallization and distillation. The structures of the final products, intermediates and starting materials are confirmed by spectroscopic, spectrometric and analytical methods including nuclear magnetic resonance (NMR), mass spectrometry (MS) and liquid chromatography (HPLC). In the descriptions for the preparation of compounds of this invention, ethyl ether, tetrahydrofuran and dioxane are common examples of an ethereal solvent; benzene, toluene, hexanes and cyclohexane are typical hydrocarbon solvents and dichloromethane and dichloroethane are representative halohydrocarbon solvents. In those cases wherein the product is isolated as the acid addition salt the free base is obtained by techniques known to those skilled in the art.
Where the processes for the preparation of the compounds according to the invention give rise to mixture of stereoisomers, these isomers may be separated by conventional techniques such as preparative chromatography. The compounds may be prepared in racemic form, or individual enantiomers may be prepared either by enantiospecific synthesis or by resolution. The compounds may, for example, be resolved into their component enantiomers by standard techniques, such as the formation of diastereomeric pairs by salt formation with an optically active acid, such as (xe2x88x92)-di-p-toluoyl-d-tartaric acid and/or (+)-di-p-toluoyl-I-tartaric acid followed by fractional crystallization and regeneration of the free base. The compounds may also be resolved by formation of diastereomeric esters or amides, followed by chromatographic separation and removal of the chiral auxiliary. Alternatively, the compounds may be resolved using a chiral HPLC column.
During any of the processes for preparation of the compounds of the present invention, it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry, ed. J. F. W. McOmie, Plenum Press, 1973; and T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, John Wiley and Sons, 1991. The protecting groups may be removed at a convenient subsequent stage using methods known from the art.
The term xe2x80x9chalogenxe2x80x9d shall include iodine, bromine, chlorine and fluorine.
The term xe2x80x9calkylxe2x80x9d shall mean straight or branched chain alkanes of one to six carbon atoms, or any number within this range. For example, alkyl radicals include, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, 3-(2-methyl)butyl, 2-pentyl, 2-methylbutyl, neopentyl, n-hexyl, 2-hexyl and 2-methylpentyl. Similarly, xe2x80x9calkenylxe2x80x9d and xe2x80x9calkynylxe2x80x9d groups include straight and branched chain alkenes and alkynes having 2 to 8 carbon atoms, or any number within this range.
The term xe2x80x9calkoxyxe2x80x9d shall denote an oxygen ether radical of the above described straight or branched chain alkyl groups. For example, methoxy, ethoxy, n-propoxy, sec-butoxy, t-butoxy, n-hexyloxy and the like.
The term xe2x80x9carylxe2x80x9d indicates aromatic groups such as phenyl and naphthyl.
The term xe2x80x9caralkylxe2x80x9d means a C1-C6 alkyl group substituted with an aryl group (e.g., benzyl, phenylethyl). Similarly, the term xe2x80x9caralkenylxe2x80x9d means a C2-C6 alkenyl group substituted with an aryl group.
The term xe2x80x9cheteroarylxe2x80x9d as used herein represents a stable five or six membered monocyclic aromatic ring system or a nine or ten membered benzo-fused heteroaromatic ring system which consists of carbon atoms and from one to three heteroatoms selected from N, O or S. The heteroaryl group may be attached at any heteroatom or carbon atom which results in the creation of a stable structure. Examples of heteroaryl groups include, but are not limited to pyridyl, pyrimidinyl, thienyl, furanyl, imidazolyl, isoxazolyl, oxazolyl, pyrazolyl, pyrrolyl, thiazolyl, thiadiazolyl, triazolyl, benzimidazolyl, benzofuranyl, benzothienyl, benzisoxazolyl, benzoxazolyl, indazolyl, indolyl, benzothiazolyl, benzothiadiazolyl, benzotriazolyl, quinolinyl or isoquinolinyl. Preferred heteroaryl groups include pyridyl, pyrimidinyl, thiazolyl, imidazolyl, benzimidazolyl, quinolinyl and isoquinolinyl.
The term xe2x80x9ccycloalkylxe2x80x9d as used herein shall represent a stable 3-8 membered monocyclic, saturated ring system, for example cyclopentyl, cyclohexyl, and the like. Similarly, the term xe2x80x9cheterocycloalkylxe2x80x9d shall represents a stable 3-8 membered monocyclic or 9-10 membered bicyclic, saturated or partially unsaturated ring system containing one to three heteroatoms selected from the group consisting of N, O and S. Suitable examples of heterocycloalkyl groups include, but are not limited to pyrrolidinyl, pyrazolidinyl, piperidinyl, piperazinyl, dioxanyl, morpholinyl, dithienyl, thiomorpholinyl, 1,3,4-trihydroisoquinolinyl, 2,3,4-trihydroquinolinyl, 1,2,3,4-tetrahydroquinolinyl, 1,2,3,4-tetrahydroisoquinolinyl, and the like. The heterocycloalkyl may be attached at any heteroatom or carbon atom which results in the creation of a stable structure.
The term xe2x80x9ccarbonylxe2x80x9d shall denote 
The term xe2x80x9caminoxe2x80x9d shall mean xe2x80x94NH2. The term xe2x80x9ccarbonylaminoxe2x80x9d shall denote 
The term, xe2x80x9caminocarbonylxe2x80x9d shall denote 
The term xe2x80x9csulfonylaminoxe2x80x9d shall denote 
The term xe2x80x9ccyclic secondary aminexe2x80x9d shall denote any ring structure containing a N atom and capable of binding at the nitrogen atom. Suitable examples include 1,2,3,4-tetrahydroisoquinolinyl, 1,2,3,4-tetrahydroquinolinyl, morpholinyl, piperidinyl, and the like.
The term xe2x80x9cdi(unsubstituted or substituted arylsulfonyl)aminoxe2x80x9d, shall denote an amine group substituted with two arylsulfonyl groups, where the aryl sulfonyl group may be optionally substituted and wherein the two arylsulfonyl groups and the optional substituents on the aryl sulfonyl groups are identical. Suitable examples include di(phenylsulfonyl)amino, di(napthylsulfonyl)amino, di(methylphenylsulfonyl)amino, di(methoxyphenylsulfonyl)amino, di(trifluoromethoxyphenylsulfonyl)amino di(fluorophenylsulfonyl)amino, di(trifluoromethylphenylsulfonyl)amino, di((ditrifluoromethyl)phenylsulfonyl)amino, di((methylcarbonylamino)phenylsulfonyl)amino, di(dimethylamino)phenylsulfonyl)amino, and the like.
Under standard nomenclature used throughout this disclosure, the terminal portion of the designated side chain is described first, followed by the adjacent functionality toward the point of attachment. Thus, for example, a xe2x80x9cphenylC1-C6 alkylaminocarbonylC1-C6alkylxe2x80x9d substituent refers to a group of the formula 
It is intended that the definition of any substituent or variable at a particular location in a molecule be independent of its definitions elsewhere in that molecule. It is understood that substituents and substitution patterns on the compounds of this invention can be selected by one of ordinary skill in the art to provide compounds that are chemically stable and that can be readily synthesized by techniques known in the art as well as those methods set forth herein.
When a particular group is xe2x80x9csubstitutedxe2x80x9d (e.g., aryl, heteroaryl, cycloalkyl, heterocycloalkyl), that group may have one or more substituents, preferably from one to five substituents, more preferably from one to three substituents, most preferably from one to two substituents, independently selected from the list of substituents.
The term xe2x80x9csubjectxe2x80x9d as used herein, refers to an animal, preferably a mammal, most preferably a human, who has been the object of treatment, observation or experiment.
The term xe2x80x9ctherapeutically effective amountxe2x80x9d as used herein, means that amount of active compound or pharmaceutical agent that elicits the biological or medicinal response in a tissue system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician, which includes alleviation of the symptoms of the disease or disorder being treated.
As used herein, the term xe2x80x9ccompositionxe2x80x9d is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combinations of the specified ingredients in the specified amounts.
The present invention therefore provides a method of treating a condition selected from an eating disorder, obesity, bulimia nervosa, diabetes, binge eating, anorexia nervosa, dyslipidimia, hypertension, memory loss, epileptic seizures, migraine, sleep disturbances, pain, sexual/reproductive disorders, depression, anxiety, cerebral hemorrhage, shock, congestive heart failure, nasal congestion or diarrhea, in a subject in need thereof, which comprises administering any of the compounds as defined herein, in a quantity effective to treat said condition. The compound may be administered to a patient by any conventional route of administration, including, but not limited to, intravenous, oral, subcutaneous, intramuscular, intradermal and parenteral. The quantity of the compound that is effective for treating a condition as described above is between 0.1 mg per kg and 20 mg per kg of subject body weight.
The present invention also provides pharmaceutical compositions comprising one or more compounds of this invention in association with a pharmaceutically acceptable carrier. Preferably these compositions are in unit dosage forms such as tablets, pills, capsules, powders, granules, sterile parenteral solutions or suspensions, metered aerosol or liquid sprays, drops, ampoules, autoinjector devices or suppositories; for oral parenteral, intranasal, sublingual or rectal administration, or for administration by inhalation or insufflation. Alternatively, the composition may be presented in a form suitable for once-weekly or once-monthly administration; for example, an insoluble salt of the active compound, such as the decanoate salt, may be adapted to provide a depot preparation for intramuscular injection. For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical carrier, e.g. conventional tableting ingredients such as corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, and other pharmaceutical diluents, e.g. water, to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a pharmaceutically acceptable salt thereof. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective dosage forms such as tablets, pills and capsules. This solid preformulation composition is then subdivided into unit dosage forms of the type described above containing from 5 to about 1000 mg of the active ingredient of the present invention. The tablets or pills of the novel composition can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of material can be used for such enteric layers or coatings, such materials including a number of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate.
The liquid forms in which the novel compositions of the present invention may be incorporated for administration orally or by injection include, aqueous solutions, suitably flavoured syrups, aqueous or oil suspensions, and flavoured emulsions with edible oils such as cottonseed oil, sesame oil, coconut oil or peanut oil, as well as elixirs and similar pharmaceutical vehicles. Suitable dispersing or suspending agents for aqueous suspensions, include synthetic and natural gums such as tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, polyvinyl-pyrrolidone or gelatin.
The method of treating a condition selected from eating disorder, obesity, bulimia nervosa, diabetes, binge eating, anorexia nervosa, dyslipidimia, hypertension, memory loss, epileptic seizures, migraine, sleep disturbances, pain, sexual/reproductive disorders, depression, anxiety, cerebral hemorrhage, shock, congestive heart failure, nasal congestion or diarrhea, described in the present invention may also be carried out using a pharmaceutical composition comprising any of the compounds as defined herein and a pharmaceutically acceptable carrier. The pharmaceutical composition may contain between about 5 mg and 1000 mg, preferably about 10 to 500 mg, of the compound, and may be constituted into any form suitable for the mode of administration selected. Carriers include necessary and inert pharmaceutical excipients, including, but not limited to, binders, suspending agents, lubricants, flavorants, sweeteners, preservatives, dyes, and coatings. Compositions suitable for oral administration include solid forms, such as pills, tablets, caplets, capsules (each including immediate release, timed release and sustained release formulations), granules, and powders, and liquid forms, such as solutions, syrups, elixers, emulsions, and suspensions. Forms useful for parenteral administration include sterile solutions, emulsions and suspensions.
Advantageously, compounds of the present invention may be administered in a single daily dose, or the total daily dosage may be administered in divided doses of two, three or four times daily. Furthermore, compounds for the present invention can be administered in intranasal form via topical use of suitable intranasal vehicles, or via transdermal skin patches well known to those of ordinary skill in that art. To be administered in the form of a transdermal delivery system, the dosage administration will, of course, be continuous rather than intermittent throughout the dosage regimen.
For instance, for oral administration in the form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic pharmaceutically acceptable inert carrier such as ethanol, glycerol, water and the like. Moreover, when desired or necessary, suitable binders, lubricants, disintegrating agents and coloring agents can also be incorporated into the mixture. Suitable binders include, without limitation, starch, gelatin, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum and the like.
The liquid forms may include suitably flavored suspending or dispersing agents such as the synthetic and natural gums, for example, tragacanth, acacia, methyl-cellulose and the like. For parenteral administration, sterile suspensions and solutions are desired. Isotonic preparations which generally contain suitable preservatives are employed when intravenous administration is desired.
The compound of the present invention can also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles, and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine or phophatidylcholines.
Compounds of the present invention may also be delivered by the use of monoclonal antibodies as individual carriers to which the compound molecules are coupled. The compounds of the present invention may also be coupled with soluble polymers as targetable drug carriers. Such polymers can include polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamidephenol, polyhydroxyethylaspartamidephenol, or polyethyl-eneoxidepolylysine substituted with palmitoyl residue. Furthermore, the compounds of the present invention may be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and cross-linked or amphipathic block copolymers of hydrogels.
Compounds of this invention may be administered in any of the foregoing compositions and according to dosage regimens established in the art whenever treatment of disorders of the central nervous system is required.
The daily dosage of the products may be varied over a wide range from 5 to 1,000 mg per adult human per day. For oral administration, the compositions are preferably provided in the form of tablets containing, 5.0, 10.0, 15.0, 25.0, 50.0, 100, 250 and 500 milligrams of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated. An effective amount of the drug is ordinarily supplied at a dosage level of from about 0.1 mg/kg to about 20 mg/kg of body weight per day. Preferably, the range is from about 0.2 mg/kg to about 10 mg/kg of body weight per day, and especially from about 0.5 mg/kg to about 10 mg/kg of body weight per day. The compounds may be administered on a regimen of 1 to 4 times per day.
Optimal dosages to be administered may be readily determined by those skilled in the art, and will vary with the particular compound used, the mode of administration, the strength of the preparation, the mode of administration, and the advancement of the disease condition. In addition, factors associated with the particular patient being treated, including patient age, weight, diet and time of administration, will result in the need to adjust dosages.
Pharmaceutical compositions containing one or more of the compounds of the invention described herein as the active ingredient can be prepared by intimately mixing the compound or compounds with a pharmaceutical carrier according to conventional pharmaceutical compounding techniques. The carrier may take a wide variety of forms depending upon the desired route of administration (e.g., oral, parenteral). Thus for liquid oral preparations such as suspensions, elixirs and solutions, suitable carriers and additives include water, glycols, oils, alcohols, flavoring agents, preservatives, stabilizers, coloring agents and the like; for solid oral preparations, such as powders, capsules and tablets, suitable carriers and additives include starches, sugars, diluents, granulating agents, lubricants, binders, disintegrating agents and the like. Solid oral preparations may also be coated with substances such as sugars or be enteric-coated so as to modulate major site of absorption. For parenteral administration, the carrier will usually consist of sterile water and other ingredients may be added to increase solubility or preservation. Injectable suspensions or solutions may also be prepared utilizing aqueous carriers along with appropriate additives.
For the treatment of disorders of the central nervous system, the pharmaceutical compositions described herein will typically contain from 1 to about 1000 mg of the active ingredient per dosage; one or more doses per day may be administered. Determination of optimum doses and frequency of dosing for a particular disease state or disorder is within the experimental capabilities of those knowledgeable in the treatment of central nervous system disorders. The preferred dose range is 1-100 mg/kg.
As modulators of the NPY5 receptor, the compounds of Formula I are useful for treating feeding disorders such as obesity, anorexia nervosa and bulimia nervosa, and abnormal conditions such as epilepsy, depression, anxiety and sexual/reproductive disorders in which modulation of the NPY5 receptor may be useful. The compounds compete with the endogenous ligands NPY and PYY and possibly non-endogenous ligands, and bind to the NPY5 receptor. In addition, the compounds demonstrate antagonist activity by antagonizing the action of NPY upon binding to the Y5 receptor.
The compounds described herein are ligands of the NPY5 receptor, but are not necessarily limited solely in their pharmacological or biological action due to binding to this or any neuropeptide, neurotransmitter or G-protein coupled receptor. For example, the described compounds may also undergo binding to dopamine or serotonin receptors. The compounds described herein are potentially useful in the regulation of metabolic and endocrine functions, particularly those associated with feeding, and as such, may be useful for the treatment of obesity. In addition, the compounds described herein are potentially useful for modulating other endocrine functions, particularly those controlled by the pituitary and hypothalamic glands, and therefore may be useful for the treatment of inovulation/infertility due to insufficient release of luteinizing hormone (LH).
The present invention comprises pharmaceutical compositions containing one or more of the compounds of Formula (I).
Abbreviations used in the specification, particularly the Schemes and Examples, are as follows:
The following examples describe the invention in greater detail and are intended to illustrate the invention, but not to limit it. All compounds were identified by a variety of methods including nuclear magnetic resonance spectroscopy, mass spectrometry and in some cases, infrared spectroscopy and elemental analysis. Nuclear magnetic resonance (300 MHz NMR) data is reported in parts per million downfield from tetramethylsilane. Mass spectra data is reported in mass/charge (m/z) units. Unless otherwise noted, the materials used in the example were obtained from readily available commercial sources or synthesized by standard methods known to those skilled in the art.